They are the main two publications with the "Modern-dayý Pračlovek" collection (Modern Caveman). The primary notion was to depict caveman drawings in a quite simple way and products which have been applied at that time... but also inside our days. The first one — “Kuchyňa Pračloveka” (Caveman's Kitchen) — is https://maplepublishers.com/blog/popular-self-publishing-trends-of-this-year/